Hypertensive disorders of pregnancy linked to increased stroke risk

The risks of any stroke, hemorrhagic stroke, and ischemic stroke are greater in patients exposed to hypertensive disorders of pregnancy (HDP), according to a recent study.

HDP causes significant strain in patients, potentially affecting their physiology through endothelial changes. There may be links between these changes and vascular pathologies such as the cardiovascular system, renal system, and neurological system.

Associations between HDP and cardiovascular disease, chronic kidney disease, and end-stage kidney disease have been determined. However, the effects of HDP on the neurological system are not properly understood.

The risk factors, prognoses, pathophysiology, and epidemiology differ between ischemic and hemorrhagic strokes. Ischemic stroke has a significantly greater incidence rate than hemorrhagic stroke and is linked to blockage of an artery providing a brain tissue region.

Age, previous cerebrovascular accident, history of hypertension, smoking, poor diet, and other factors have been linked to increased ischemic stroke risk, but the association between HDP and ischemic stroke is unknown. Similarly, hypertension, smoking, excessive alcohol intake, and elevated waist-to-hip ratio are associated with hemorrhagic stroke, but HDP does not have a clear association.

To determine the association between HDP and long-term risk of maternal stroke, investigators conducted a study using data from the PubMed, Web of Science, and CINAHL databases. A systematic search of these databases was performed from their inception to December 19, 2022.

Studies were included if they contained a population of pregnant women, exposure to HPV of interest, a comparison group not exposed, and a primary outcome of cerebrovascular accident (CVA) or ischemic or hemorrhagic stroke. Established clinical criteria, hospitals records, and self-reporting of diagnosis were used to determine exposure, CVA, and stroke.

Titles and abstracts were analyzed by 2 independent researchers, reviewing for case-control or cohort studies conducted on human participants and available in English. Included studies also reported on at least 20 cases, measured the history of HDP and stroke outcome, reported an association between HDP and stroke, and showed outcome diagnosis after exposure diagnosis.

Exclusion criteria included having an outcome diagnosis less than 3 months postpartum, focusing on CVA only during pregnancy or in the offspring, not being available in English, and being a case report, case series, commentary, note, editorial, and published after December 19, 2022.

The quality and risk of bias of studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. A third reviewer was consulted when the 2 independent researchers could not reach a consensus.

There were 24 studies included in the final review, 9 of which evaluated more than 1 HDP, and 9 which analyzed the composite exposure of any HDP. There were 10,632,808 participants across the 24 studies, with significant differences in sample size between individual studies. A low risk of bias was found in 15 studies, and a moderate risk in 9.

An effect analysis on the association between HDP exposure and stroke outcome was reported by 9 of the 24 studies.Two studies focused on the association between HDP and ischemic stroke, and 2 on HDP and hemorrhagic stroke.

A pooled estimate of aRR 1.74 was found for HDP and any stroke, aRR 1.65 for HDP and ischemic stroke, and aRR 2.26 for HDP and hemorrhagic stroke. While studies on HDP and ischemic stroke showed no observed heterogeneity, studies on HDP and hemorrhagic stroke showed moderate heterogeneity.

Association between preeclampsia (PE) and any stroke was seen in 14 studies, 1 of which was an outlier and removed. After this removal, a pooled effect measure of aRR 1.75 was observed. This indicated relatively low heterogeneity.

The association between PE and hemorrhagic stroke was evaluated in 7 studies, showing a pooled effect estimate of aRR 2.77. Overall, PE and hemorrhagic stroke had a greater heterogeneity than PE and ischemic stroke.

Gestational hypertension, another HDP, had a pooled effect measure of aRR 1.23 when associated with any stroke, aRR 1.35 when associated with ischemic stroke, and aRR 2.66 when associated with hemorrhagic stroke.

Overall, associations were found between HDP and any stroke, ischemic stroke, and hemorrhagic stroke. A history of HDP increased the risk of patients developing stroke later in life, with the association varying between HDP subtypes.

Reference

Brohan M, Daly F, Kelly L, et al. Hypertensive disorders of pregnancy and long-term risk of maternal stroke – A systematic review and meta-analysis. American Journal of Obstetrics & Gynecology. 2023. doi:10.1016/j.ajog.2023.03.034